RG-improved single-particle inclusive cross sections and forward-backward asymmetry in $t\bar t$ production at hadron colliders

TL;DR

This paper employs soft-collinear effective theory to improve predictions for top-quark pair production observables at hadron colliders, including cross sections and asymmetries, by resumming large logarithms and analyzing power corrections.

Contribution

It introduces a SCET-based framework for renormalization-group improved calculations of 1PI observables in top-quark production, incorporating subleading terms for better accuracy.

Findings

Predictions for total cross section agree well with invariant-mass methods when subleading terms are included.

Threshold expansion in 1PI kinematics has significant power corrections but remains reliable with proper terms.

Resummed predictions at NLO+NNLL improve the accuracy of top-quark observable calculations.

Abstract

We use techniques from soft-collinear effective theory (SCET) to derive renormalization-group improved predictions for single-particle inclusive (1PI) observables in top-quark pair production at hadron colliders. In particular, we study the top-quark transverse-momentum and rapidity distributions, the forward-backward asymmetry at the Tevatron, and the total cross section at NLO+NNLL order in resummed perturbation theory and at approximate NNLO in fixed order. We also perform a detailed analysis of power corrections to the leading terms in the threshold expansion of the partonic hard-scattering kernels. We conclude that, although the threshold expansion in 1PI kinematics is susceptible to numerically significant power corrections, its predictions for the total cross section are in good agreement with those obtained by integrating the top-pair invariant-mass distribution in pair invariant-mass kinematics, as long as a certain set of subleading terms appearing naturally within the SCET formalism is included.